To accommodate people's busy lifestyles, mobile electronic devices such as personal digital assistants, smart phones, tabular computers have become indispensable. As an example, a smart phone equipped with a touch screen may not only include each feature provided by a traditional communication device, but may also include a built-in operation system that carries out versatile tasks such as document editing, e-mail serving, web serving, multimedia playing, photo shooting, and instant communication, and thus its usage has surpassed all the other electronic devices. Thus, the endurance of such electronic device is critical to meet the user's satisfaction.